Antiskid attachment for footwear and universal traction enhancement method

ABSTRACT

An antiskid attachment for footwear is described wherein the traction increases when lateral skidding occurs. The attachment comprises of a multitude of skid-resisting elements positioned between the shoe sole and the surface, and flexible linkage used to ensure appropriate positioning of the elements allowing natural walking and running movement and easy application with virtually any type of footwear. The attachment ensures improved traction on ice and snow, thereby reducing the possibility of slipping during inclement weather, without danger to the user or damage to surfaces when used on ice-free surfaces. The inventive universal method of traction enhancement using polyhedral elements is explained as deployed in, but not limited to, the present footwear attachment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of U.S. 60/759,288, filed 2006 Jan. 17.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

Not Applicable.

BACKGROUND OF THE INVENTION

Shoes for everyday wear provide poor traction on slippery surfaces, such as ice and packed snow. Special shoes for outdoor use (e.g., winter boots, hiking footwear) provide better traction on packed snow but are almost as useless on slippery ice, especially during the season when the outdoor temperature is changing around the freezing point, and during periods of freezing rain.

The principal drawbacks of the existing solutions are: They are bulky, difficult to put on or take off, dangerous to the user and damaging to the flooring when used indoors because of the sharp element used to create traction, or, when sharp elements are not employed, inefficient on black ice.

Thus, one of the most well known “Traction augmentation device”, described in U.S. Pat. No. 5,909,945 (Noy, 1999), may have similar usability and efficiency on packed snow, but is bulkier and its efficiency on ice is minimal. Another well-known product, “Cleated outer sole”, U.S. Pat. No. 5,335,429 (Hansen; Ross, 1994), is efficient on both snow and ice but is bulky and must be removed whenever the surface becomes smooth (for the danger of slipping or damaging the floor).

A similarly looking device is disclosed in Russian Federation patent RU 2149573 (Kryuk, Raginsky, 1999). Compared to the examples sited above, it is comfortably small, simple in construction, easy to use and does not present an instant danger of slipping on ceramic (or other hard and smooth) floors. However, in this device the traction is achieved through the presence of sharp burrs on the welded chain constituting the traction element, which will cause damage to most indoor floors, and the way the chain elements are positioned against the shoe sole makes the device prone to cuts and ruptures and altogether insecure on the shoe.

Finally, the devices provided in prior arts use straightforward sliding friction as the only means of traction enhancement. The inventive method described herein deploys rolling friction phase as a means of traction enhancement, and therefore provides superior results. The underlying traction enhancement method can be used in various devices and applications whenever the traction between two surfaces needs to be enhanced without making either of them excessively deteriorating to other surfaces.

Other objects and advantages will become apparent from a consideration of the following specification and the accompanying drawings.

BRIEF SUMMARY OF THE INVENTION

Antiskid and traction improvement devices that have been described in the art provide this capability by a variety of different means. In most cases, they are designed as overshoes and are equipped with sharp elements. Those qualities make many of the existing designs (a) too bulky, (b) difficult to put on and take off, and (c) unsafe to manipulate. In addition, the devices equipped with sharp elements (cleats, crampons) render the footwear extremely slippery when used on the smooth stone floor (e.g., inside the mall) and/or damage the flooring and therefore must be taken off before entrance. In case of vehicle tires, introduction of the crampons decreases their traction coefficient on clean roadways while making the use of such tires detrimental to pavement. Conversely, those devices without sharp elements are not efficient on icy (and similar) surfaces.

The antiskid attachment of the present invention is an improvement over the existing and prior art devices in that it is designed as a device easy to fasten and remove, small enough to carry along, and cheap and simple to produce. The design is flexible to work with almost any type of footwear and provides an improved degree of traction on both packed snow and ice without impeding normal walking and running movement. Having no cleats, crampons or other sharp or abrasive parts, the device is not detrimental to most flooring types. Using the inventive method of traction enhancement described herein, the device remains sufficiently stable on smooth stone floors, permitting transitory use of the device indoors, thus minimizing the inconvenience of changing or removing footwear every time one enters indoors.

The inventive method of traction enhancement described herein, may be used in various anti-slip applications, including but not limited to shoe soles, tires and non-slip flooring.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1—overall view of the present invention in preferred embodiment;

FIG. 2—detailed view of a polyhedral skid-resisting element in preferred embodiment, illustrating tetrahedral nature of the elements;

FIG. 3—detailed view of the self-adjusting linkage;

FIG. 4—detailed view of the swivel part of the self-adjusting linkage;

FIG. 5—overall view of the present invention in preferred embodiment attached to footwear;

FIG. 6—diagram illustrating the performance of the polyhedral skid-resisting element;

FIG. 7—diagram illustrating the performance of the self-adjusting linkage;

FIG. 8—diagram demonstrating contact pressure redistribution;

FIG. 9 (A, B)—other possible applications of the traction enhancement method.

DETAILED DESCRIPTION OF THE INVENTION

The present invention represents an improved anti-skid attachment for footwear, that integrates performance, light weight, convenience of use and manufacturability. Specifically, the invention comprises a multitude of skid-resisting elements (1), preferably of, but not limited to, tetrahedral shape, positioned between the footwear (2) and the surface (3) (see FIG. 5) as an attachment, or embedded. The skid-resisting elements may be built specifically for the purpose, with the shape of the elements varying from a pyramid with triangular faces (tetrahedron) to a conical shape but not limited to the said shapes. For mass-market applications, a standard single jack chain or double loop (double jack) chain may be used instead. FIG. 2 explains the tetrahedral nature of the single jack chain links used in preferred embodiment. The device further comprises front and back flexible linkage parts, each consisting of the elastic loops (4, 5) and swivel connectors (6) connecting the elastic loops to the skid-resisting elements.

The device is attached to the footwear by pulling the front elastic loop over the toe of the shoe, stretching it until the front skid-resisting elements are positioned without slack under the front part of the shoe, with swivel connectors positioned flush with the sides of the sole as shown on FIG. 3, then stretching the back loop over the heel of the shoe (FIG. 5).

The swivel connectors (see FIG. 4) consist of the swivel part (7) and an additional link (8) inserted between the swivel and the skid-resisting elements (links of jack chain in the preferred embodiment). This combination facilitates the process of putting the device on the shoe by reducing susceptibility to tangling and by eliminating the need to define the “top” and the “bottom” of the attachment in order to achieve the desired antiskid effect.

In addition, the connectors are designed as levers, and are shaped in such a way that they are retained in the correct position (described above, and as shown on FIG. 3 and FIG. 7) by a relatively small tension exerted by the soft elastic loop (4), as this force, applied to the longer moment arm, creates sufficient force to secure the vertical parts of the swivel against the sides of the sole. In the previously known anti-slip attachments, the elastic members must withstand the strain caused by the anti-slip action, and therefore they are made noticeably more rigid and hard to stretch.

The elastic loops are made of tubular or round-profile elastomeric material which facilitates attaching of the device to the shoes and self-adjustment of the antiskid elements on the footwear.

Furthermore, this configuration of the connectors protects the elastic loops from being damaged or cut when stepping on sharp objects, as the elastic parts are located around the vamp and heel of the shoe and not under them nor against the outsole edges.

The inventive method of the anti-slip enhancement is based on the following. All known antiskid devices are designed to increase sliding friction only. This provides adequate traction on packed snow and rough surfaces. However, traction on ice has a specific nature similar to friction between lubricated surfaces, with sliding friction being extremely low, and therefore cleats and crampons are used to increase the friction factor in the majority of antiskid devices and winter tires that are currently available. For reasons explained above, cleats and crampons may be unacceptable in certain applications.

The present inventive method suggests transition from sliding to rolling friction as a means of gaining additional control over skidding. Spheres, being polyhedrons with infinite number of summits, offer minimal resistance to rolling. However, the rolling friction increases as the number of summits decreases. The least possible number of summits for a three-dimensional solid is equal to four. Hence, the tetrahedron will create maximum possible rolling friction and is the basic shape for the preferred embodiment, while other polyhedral shapes may be utilized as well.

The suggested inventive antiskid elements provide traction improvement as compared to regular ribbed or grooved surfaces and spikeless chains in the following way. Forced by lateral skidding force, the elements will attempt to turn, causing redistribution of pressure from 2 to 1 point per element (see chain “footprints” on FIG. 8). This will increase the pressure in contact points, sharply augmenting resistance to sliding in the points of contact, thereby increasing traction and delaying the breakaway to sliding friction, thereafter acting as conventional crampons or studs.

While many other attachments using chains may look similar, they do not have the benefits of the polyhedral shape of the present antiskid elements and therefore are less efficient on ice and other hard slippery surfaces. The existing attachments with carbonized steel crampons and cleats may be more efficient on plain hard ice, but are extremely uncomfortable to use on hard surfaces, such as tiled floors, and are dangerous due to increased slipping, while being detrimental to most surfaces. In addition, driving a vehicle is not safe with those devices attached to the footwear, if possible at all. Similarly, spiked tires have inferior friction on a clean asphalt or concrete roadway and are deteriorating for paved roads. The present invention does not have the above disadvantages, and has an additional advantage of providing traction “on demand”, keeping friction elements suppressed until sliding has occurred. This is applicable to embedded antiskid elements as having similar characteristics.

The use of the inventive antislip elements and method in other applications brings equivalent benefits; e.g.: winter tires (FIG. 9A), non-slip floors (FIG. 9B). 

1. An antiskid attachment for footwear comprising: a multitude of skid-resisting elements positioned between the shoe sole and the surface, providing enhanced traction; flexible linkage keeping the skid-resisting elements in appropriate position, allowing natural walking and running movement and easy application of the attachment;
 2. The attachment of claim 1, wherein said elements have polyhedral shape, with preference given but not limited to a tetrahedral or pentahedral shape;
 3. The attachment of claim 1, wherein said elements have pyramidal or conical shape;
 4. The attachment of claim 1, wherein the flexible linkage includes specially shaped connectors ensuring self-adjustment of the skid-resisting elements' position against the sole of the footwear without excessive tension of the elastic members;
 5. The attachment of claim 1, wherein the connectors are pivotally connected to the elastic members;
 6. The attachment of claim 1, wherein the elastic members of the linkage are made of tubular or cylindrical material;
 7. The attachment of claim 2, wherein a single jack or double jack chain is used, with the links of the said chain behaving as skewed tetrahedrons;
 8. The traction enhancement method wherein the resistance to skidding is achieved by positioning of the friction elements, mechanically equivalent to the polyhedral solids and having polyhedral, or mechanically equivalent to polyhedral, cross sections, between the slippery surface and the object the position or movement of which needs to be stabilized on the slippery surface.
 9. The traction enhancement method of claim 8, wherein the enhancement of antislip properties is achieved in part through the introduction of more efficient rolling friction conditions, thus delaying the breakaway to sliding friction. 